If not using a video otoscope to make the incision, insert the tip of the catheter into the otoscope and guide it ventrally toward the eardrum. Once the eardrum can be seen clearly, quickly advance the catheter into the bulla at the most ventral position.
Regardless of whether the incision is made with a video or surgical otoscope, any bleeding indicates that it was not made in the proper position. Damage to either the pars flaccida or the malleus bone results in bleeding, which can slow healing.
Laser myringotomy is usually reserved for cases with pronounced eardrum thickening that prevents a polypropylene catheter incision. When using a CO2 laser, position the laser tip at the appropriate location opposite and ventral to the malleus. Using a 500-msec time and 4-watt power setting, a single laser pulse will make a circular opening in the eardrum. If the incision is not large or deep enough, another single pulse may be used adjacent to the first opening. A diode laser tip has to touch the eardrum as the energy is supplied to cut through the eardrum.
Step 4. With the catheter method, insert and advance the catheter as deep as it will go. With the spinal needle or the curette method, make the incision and withdraw.
Step 5. Insert an open-ended catheter into the bulla. If using a surgical otoscope head, poor visualization can make threading a catheter through the myringotomy incision difficult.
Author Insight: Access to the material produced in the tympanic cavity allows bacterial culture and antibiotic sensitivity testing of this material as well as cytologic analysis of the exudate.
Step 6. To sample the bulla, withdraw any fluid in the bulla through the catheter using a 5-mL syringe. Some fluid will reach the syringe, but in some cases there will be scant fluid filling the lumen of the catheter. Withdraw the catheter from the bulla and apply the contents to the cotton-tipped applicator (for cytologic examination) and to the culturette (for bacterial culture).
Step 7. To flush the bulla, insert an open-ended catheter until it hits bone. Flushing fluid (either 0.9% saline solution or tap water) overflows into the external ear canal, from which it is then suctioned out. Irrigate the bulla through high pressure with a 60-mL syringe or a mechanical irrigator, observing for material flushed out of the incision. Suction fluid from the bulla, and repeat flush and suction until flushing solution exits the incision without any material. Suction as much fluid as possible from the bulla.